The invention discloses a multi-functional steel structure crack monitoring test platform, and relates to the technical field of steel structure crack monitoring. The test platform comprises a monitoring mechanism, a conveying mechanism, a control mechanism and a control case. The control case is fixedly arranged on the top of the monitoring mechanism, and the control mechanism is fixedly arranged on the front face of the monitoring mechanism. By arranging a hydraulic cylinder as a driving source, the hydraulic cylinder effectively drives a hydraulic rod to perform extension operation and drives a connecting support to vertically float up and down, so that the use height of the connecting support is adjusted according to the size and height of a detected steel structure, and the test platform is suitable for monitoring the steel structure; and meanwhile, the steel structure is conveyed into the monitoring mechanism through the conveying mechanism, and ultrasonic detection is performed on the steel structure through the combined action of radio frequency coils, infrared induction scanners and ultrasonic probes which are arranged at the bottoms of the two sides of the connecting support, so that the detection comprehensiveness is guaranteed, the monitoring effect is effectively improved, and the practicability is enhanced.